Oefenweb / php-statistics

     *

     * @return void

     */

    public function testVariancePopulationIntegers()

    {

        $values = [2, 4, 4, 4, 5, 5, 7, 9];

        $sample = false;

        $result = Statistics::variance($values, $sample);

        $expected = 4;

        $this->assertSame($expected, $result);

    }

    /**

     * Tests `variance`.

     *

     * @return void

     */

    public function testStandardDeviationSampleFloats()

    {

        $values = [1.5, 2.5, 2.5, 2.75, 3.25, 4.75];

        $sample = true;

        $result = Statistics::standardDeviation($values, $sample);

        $expected = 1.081087;

        $this->assertEquals($expected, $result, '', pow(10, -4));

    }

    /**

     * Tests `standardDeviation`.

     *

     * @return void

     */

    public function testStandardDeviationPopulationIntegers()

    {

        $values = [2, 4, 4, 4, 5, 5, 7, 9];

        $sample = false;

        $result = Statistics::standardDeviation($values, $sample);

        $expected = 2.0;

        $this->assertSame($expected, $result);

    }

    /**

     * Tests `standardDeviation`.

     *

     * @return void

     */

    public function testStandardDeviationPopulationFloats()

    {

        $values = [1.5, 2.5, 2.5, 2.75, 3.25, 4.75];

        $sample = false;

        $result = Statistics::standardDeviation($values, $sample);

        $expected = 0.9868;

        $this->assertEquals($expected, $result, '', pow(10, -4));

    }

    /**

     * Tests `range`.